1. Field of the Invention
This invention concerns a method for diminishing the pungent aroma characteristics of onions, and further concerns the resultant onion products.
2. Description of the Prior Art
Onions are a major food commodity in many countries. Various species of onion are known, having different taste and aroma characteristics. In general however, it is common for onions to contain volatile lachrymator compounds and compounds which give rise to a pungent or spicy taste sensation.
In times past it was possible to purchase so-called sweet onions year around. By this is meant onions having a sufficiently mild flavor that could be used in salads, sandwiches, and similar applications without overwhelming the flavor of the other ingredients. More recently, however, it has become difficult to obtain this preferred type of onion. To the contrary, most of the onions which are now obtainable during the cold months on a commercial basis are characterized by an extremely hot flavor.
Certain species of onions, for example Vidalia onions grown in a small area of the state of Georgia, are especially prized for their mild flavor and aroma. However, these onions are only available from May through September. Upon ageing, there is an increase in compounds such as propionaldehyde which increase lachrymator characteristics and impart a harsh or irritating taste and aroma.
There has thus developed a need for a system for rendering hot onions sufficiently mild to facilitate their use in salads, sandwiches, and similar applications in which the use of sweet onions is preferred.
The treatment of food products to extract volatile components is well known. For example, various fruit and vegetable products have been subjected to drying treatments to remove water. The resultant dried products are useful because of prolonged storage life and light weight. The drying techniques may involve treatment under vacuum conditions in frozen or unfrozen states or long exposure to an air stream under warm conditions.
In other foodstuff treatments, such as disclosed in U.S. Pat. Nos. 3,717,472 and 3,997,685, desirable volatile substances are removed from products such as coffee and tea by vacuum treatment employing condensing traps. The substances recovered from the traps are useful as flavorants for other food products.
U.S. Pat. No. 3,607,316 discloses the dehydration of onions by vacuum treatment which removes substantially all water and other volatile substances. Because of co-distillation effects and the extensive nature of vacuum dehydration, it is quite likely that desirable flavorants and odorants are removed from the onions.
U.S. Pat. No. 4,034,118 to Martin discloses a process for achieving a mellowing or sweetening effect in onions without causing dehydration or loss of desirable flavor components. The Martin process involves the treatment of slices of onion with vinegar under refrigerated conditions for several days.
The aforesaid treatments of onions and other food products are difficult and time-consuming, and require expensive specialized equipment.
It is accordingly an object of the present invention to provide a process for causing onions to become mellower and sweeter.
It is another object of this invention to provide an onion-treating process as in the foregoing object which does not remove desirable flavor components or large amounts of water.
It is a further object of the invention to provide a process of the aforesaid nature which can be accomplished relatively quickly and with inexpensive equipment.
These and other beneficial objects and advantages will be apparent from the following description.